A very exciting new development is the growth of large crystals of pyruvate dehydrogenase (E1p) from B. stearothermophilus which diffract till 3 E on an in-house rotating anode system. Synchrotron radiation will be essential to collect higher resolution data of this thiamine diphosphate (TDP) containing enzyme which is crucial for the control of the entire multienzyme complex. The protein of the catalytic domain of dihydrolipoyl transacetylase (E2pCD) of E. faecalis is crystallized diffracting till 8 E on a rotating anode system. An increased resolution to marginally 4-5 E provided by SR is expected to reveal the architecture of the subunits in the structural core.